A5089209034- Ionic liquids properties and applications
- Electrochemical Analysis and Applications
- Advanced Battery Materials and Technologies
- Advancements in Battery Materials
- Supercapacitor Materials and Fabrication
- Advanced battery technologies research
- Advanced Battery Technologies Research
- Conducting polymers and applications
- Spectroscopy and Quantum Chemical Studies
- Analytical Chemistry and Sensors
- Extraction and Separation Processes
- Electrocatalysts for Energy Conversion
- Methane Hydrates and Related Phenomena
- Fuel Cells and Related Materials
- Electrochemical sensors and biosensors
- Atmospheric and Environmental Gas Dynamics
- Electrostatics and Colloid Interactions
- Electrohydrodynamics and Fluid Dynamics
- Hydrocarbon exploration and reservoir analysis
- Phase Equilibria and Thermodynamics
- Crystallization and Solubility Studies
- Thermodynamic properties of mixtures
- Analytical Chemistry and Chromatography
- nanoparticles nucleation surface interactions
- Theoretical and Computational Physics
Mircea cel Batran Naval Academy
2024-2025
DEVCOM Army Research Laboratory
2017-2023
United States Army Combat Capabilities Development Command
2022-2023
University of Utah
2012-2022
University of Maryland, College Park
2020
Adelphi Laboratory Center
2017-2018
Material Sciences (United States)
2015
University of Calgary
2006-2010
Queen's University
2001-2004
Alexandru Ioan Cuza University
1998
Highly concentrated electrolytes containing carbonate solvents with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) have been investigated to determine the influence of eliminating bulk solvent (i.e., uncoordinated a Li+ cation) on electrolyte properties. The phase behavior ethylene (EC)–LiTFSI mixtures indicates that two crystalline solvates form—(EC)3:LiTFSI and (EC)1:LiTFSI. Crystal structures for these were determined obtain insight into ion coordination. Between compositions,...
Molecular dynamics simulation studies of the structure and differential capacitance (DC) for ionic liquid (IL) N-methyl-N-propylpyrrolidinium bis(trifluoromethane)sulfonyl imide ([pyr13][TFSI]) near a graphite electrode have been performed as function temperature potential. The IL exhibits multilayer that extends 20−30 Å from surface. composition ion orientation in innermost layer were found to be strongly dependent on While at potentials potential zero charge (PZC), both cations anions...
Electroactive interfaces distinguish electrochemistry from chemistry and enable electrochemical energy devices like batteries, fuel cells, electric double layer capacitors. In electrolytes should be either thermodynamically stable at the electrode or kinetically by forming an electronically insulating but ionically conducting interphase. addition to a traditional optimization of adding cosolvents sacrificial additives preferentially reduce oxidize surfaces, knowledge local electrolyte...
A water-in-salt electrolyte (WiSE) offers an electrochemical stability window much wider than typical aqueous electrolytes but still falls short in accommodating high-energy anode materials, mainly because of the enrichment water molecules primary solvation sheath Li+. Herein, we report a new strategy which non-Li cosalt was introduced to alter Li+-solvation structure. The presence asymmetric ammonium salt (Me3EtN·TFSI) increases solubility LiTFSI by two times, pushes salt/water molar ratio...
Abstract Although the “water‐in‐salt” electrolyte has significantly expanded electrochemical stability window of aqueous electrolytes from 1.23 to 3 V, its inevitable hydrogen evolution under 1.9 V versus Li + /Li prevents practical use many energy‐dense anodes. Meanwhile, liquidus temperature at 17 °C restricts application below ambient temperatures. An advanced hybrid is proposed in this work by introducing acetonitrile (AN) as co‐solvent, which minimizes presence interfacial water...
While lithium hexafluorophosphate (LiPF6) still prevails as the main conducting salt in commercial lithium-ion batteries, its prominent disadvantage is high sensitivity toward water, which produces highly corrosive HF that degrades battery performance. The hydrolysis mechanism and correlation with voltage environment remain poorly understood, despite wide application of cathode. In this work, combining theoretical experimental approaches, we identified direct reaction between H2O PF6– source...
Development of safe aqueous batteries and supercapacitors critically relies on expanding the electrolyte electrochemical stability window. A novel mechanism responsible for widening window water-in-salt electrolytes (WiSEs) compared to conventional salt-in-water is suggested based molecular dynamics (MD) simulations electrolyte-electrode interface. Water exclusion from interfacial layer at positive electrode provided additional kinetic protection that delayed onset oxygen evolution...
Abstract Transition-metal dissolution from cathode materials, manganese in particular, has been held responsible for severe capacity fading lithium-ion batteries, with the deposition of transition-metal cations on anode surface, elemental form or as chelated-complexes, main contributor such degradations. In this work we demonstrate diverse experiments and calculations that, besides interfacial species anode, manganese(II) bulk electrolyte also significantly destabilizes components its unique...
Rechargeable Zn metal batteries (RZMBs) may provide a more sustainable and lower-cost alternative to established battery technologies in meeting energy storage applications of the future. However, most promising electrolytes for RZMBs are generally aqueous require high concentrations salt(s) bring efficiencies toward commercially viable levels mitigate water-originated parasitic reactions including hydrogen evolution corrosion. Electrolytes based on nonaqueous solvents avoiding these issues,...
In this work we show that homogeneous nucleation of methane hydrate can, under appropriate conditions, be a very rapid process, achieved within tens nanoseconds. agreement with recent experimental results on different systems, find the gas crystal appears as two-step process. It starts formation disordered solid-like structures, which will then spontaneously evolve to more recognizable crystalline forms. This previously elusive first-stage state is confirmed post-critical in and...
Molecular dynamics (MD) simulations of an electrolyte comprised ethylene carbonate (EC), dimethyl (DMC), and LiPF6 salt near the basal face graphite electrodes have been performed as a function electrode potential. Upon charging electrodes, less polar DMC molecule is partially replaced in interfacial layer by more EC. At negative potentials, carbonyl groups from molecules are repelled surface, while at positive we find substantial enrichment surface with groups. PF6– rapidly accumulates...
Molecular dynamics simulations were performed on N-methyl-N-propylpyrrolidinium bis(fluorosulfonyl)imide (pyr(13)FSI) room temperature ionic liquid (RTIL) confined between graphite electrodes as a function of applied potential at 393 and 453 K using an accurate force field developed in this work. The electric double layer (EDL) structure differential capacitance (DC) pyr(13)FSI was compared with the results previous study similar RTIL pyr(13)bis(trifluoromethanesulfonyl)imide (pyr(13)TFSI)...
Molecular simulations reveal that the shape of differential capacitance (DC) versus electrode potential can change qualitatively with structure surface. Whereas atomically flat basal plane graphite in contact a room-temperature ionic liquid generates camel-shaped DC, corrugated prismatic face same electrolyte exhibits bell-shaped behavior and much larger DCs at low double-layer potentials. The observed DC was correlated structural changes occurring double layer as function applied potential....
The dependence on electrode potential of the interfacial structure and differential capacitance (DC) for 1-alkyl-3-methyimidazolium bis(trifluoromethanesulfonyl)imide ([Cnmim][TFSI], n = 2, 4, 6, 8) ionic liquids (IL) near basal (flat) prismatic edge face (rough) graphite electrodes was investigated here with atomistic simulations. Overall camel-shaped DCs were observed both surfaces. generated systematically larger capacitances than atomically flat face. Although DC is almost constant at...
The double layer composition and structure of the mixed-solvent electrolyte tetramethylene sulfone/dimethyl carbonate (TMS/DMC) doped with LiPF6 near graphite surface have been investigated using molecular dynamics simulations as a function applied potential between electrodes ranging from 0 to 6 V. Three solvent compositions, TMS/DMC ratios 1:2, 1:1, 2:1 salt, were investigated. At uncharged electrodes, at interfaces was found be similar that bulk for 1:1 1:2 systems but deviated ratio 2:1....
The capacitance enhancement experimentally observed in electrodes with complex morphology of random subnanometer wide pores is an intriguing phenomena, yet the mechanisms for such are not completely understood. Our atomistic molecular dynamics simulations demonstrate that slit-geometry nanopores, a factor 2 (compared to flat electrode) possible 1-ethyl-3-methylimidazolium (EMIM)-bis(trifluoro-methylsulfonyl)imide (TFSI) ionic liquid electrolyte. This result fast charge separation inside...
The potential pathways to increase the energy storage in electric double-layer (EDL) supercapacitors using room-temperature ionic liquid electrolytes and carbon-based nanostructured electrodes are explored by molecular dynamics simulations. A systematic comparison of capacitances obtained on nanoparticles various shape dimensions showed that when electrode curvature length scale surface roughness comparable ion dimensions, a noticeable improvement capacitive is observed. nanoconfinement...
The enhancement of non-Faradaic charge and energy density stored by ionic electrolytes in nanostructured electrodes is an intriguing issue great practical importance for storage electric double layer capacitors. On the basis extensive molecular dynamics simulations various carbon-based nanoporous room temperature liquid (RTIL) electrolytes, we identify atomistic mechanisms correlations between electrode/electrolyte structures that lead to capacitance enhancement. In symmetric electrode setup...
Capacitive energy storage devices are receiving increasing experimental and theoretical attention due to their enormous potential for applications. Current research in this field is focused on the improvement of both power density supercapacitors by optimizing nanostructure porous electrodes chemical structure/composition electrolytes. However, understanding underlying correlations mechanisms electric double layer formation near charged surfaces inside nanoporous complicated complex...
In this paper we report a successful molecular simulation study exploring the heterogeneous crystal growth of sI methane hydrate along its [001] crystallographic face. The modeling has proven in past to be very challenging, and reasonable framework overcome difficulties related such systems is presented. Both microscopic mechanisms as well interfacial properties are probed. presence appropriate template, strong tendency for water molecules organize into cages around at growing interface...